Somehow or another, I have managed never to read Feynman’s famous book on Quantum Electro-Dynamics. It always seemed a little too much like work, but having found myself in the position of writing a pop-science book about quantum physics that includes a chapter on QED and Feynman diagrams, it seemed like it would probably be a good idea to get and read a copy.

An odd side effect of the mythologization of Feynman– partly his own doing, and partly the work of hero-worshipping nerds– is that it’s easy to forget just how good he was at doing this sort of thing. So much time is spent on the skirt-chasing, lock-picking, and bongo-playing that you can lose sight of the fact that he had a real gift for presenting science. The Feynman Lectures on Physics are a little dated now, but loaded with really good ideas, and this book is an excellent treatment of the subject that made his name.

This is an unusual book in a lot of ways. It’s an edited transcription of a set of four lectures he gave at UCLA in the early 80′s, and as such contains a lot of little asides and exclamations that almost certainly work better out loud than they do on the page. It’s also an uncompromising treatment of the subject, in that Feynman sets out to present QED to a general audience in some detail, and not just as a set of mad hand-waves and bold assertions. He works through the rationale for the path integral formulation of quantum mechanics almost from first princples, and goes into a surprising amount of detail about how to calculate the g-factor for an electron (way more than I was willing to attempt, that’s for sure).

And it works. On the surface, at least. It still fits in the general category of what one of my grad school professors said about the Feynman Lectures:

The thing about Feynman is that you read it, and you say “Yes! I understand! I’m doing physics!” Then you try to solve a problem, and you find that, well, that you’re not Feynman.

He’s obviously not trying to teach anybody to do real QED calculations here– he says that explicitly every five pages or so– but there’s a similar effect at work. The presentation here is so elegant and seamless that it’s a little hard to imagine someone who isn’t Feynman using this book as the basis to explain the theory to someone else. If you already know a little bit about it, this can illuminate some other aspects, and provide some tricks that you could combine with pre-existing knowledge to make a good presentation, but the book alone conveys more of a sense of understanding than actual understanding.

Lest you think I’m damning with faint praise, though, I should say that this is no mean feat. The material he presents is in many ways at a level of weird and abstract that’s comparable to anything else you’ll find in modern science, and yet he presents it in such plain language, and such a no-nonsense manner that it’s surprisingly easy to follow along, and you leave with a clearer sense of the subject than in almost any other popular book I’ve read. It’s really a masterful performance.

I highly recommend this book for anyone who is interested in the subject.

(I’ll note, though, that if you get the 2006 Princeton University Press edition (as I did), you should feel free to skip the remarkably pompous introduction by A. Zee that’s touted on the cover. Its tone is almost nothing like the book itself, and could easily create a false and negative impression of what reading it will be like.)

Comments

  1. #1 such.ire
    January 18, 2008

    There’s an archive online of footage from Feynman’s QED talks. I think it’s quite entertaining to hear some of the question-and-answer parts of the lectures, too.

  2. #2 Chad Orzel
    January 18, 2008

    There’s an archive online of footage from Feynman’s QED talks. I think it’s quite entertaining to hear some of the question-and-answer parts of the lectures, too.

    The problem is, they’re RealAudio files, and RealPlayer is indistinguishable from a virus, at least the last time I encoutnered it…

  3. #3 Åka
    January 18, 2008

    I read this book at about the same time as I was taking relativistic quantum mechanics, and I was very confused over how to translate between the usual formulation of things and Feynman’s little rotating arrows and stuff. Maybe it would work better if I would read it now.

  4. #4 Unistrut
    January 18, 2008

    There’s a program called “Real Alternative” that can play some RealMedia files without having to install their wretched player. Just do a Google search for it and pick a download site.

  5. #5 agm
    January 18, 2008

    Do they have Helix Player ported over to windows yet? Though when in XP I do just fire up Real Alternative…

  6. #6 sean
    January 18, 2008

    QED was one of the first physics books I ever read outside of high school physics. I’m a Phd now. The Lectures and Landau’s books are the best physics books I’ve come across and continue to refer to them. Personally I find the “bongo” stories and other mythologization stories completely boring.

  7. #7 sean
    January 18, 2008

    let me correct that. not “one of the first”, it was the first. That was a great summer.

  8. #8 Carl Brannen
    January 18, 2008

    Over the years I’ve bought at least 6 copies of this book as I think it is by far the best introduction to quantum mechanics for those who are interested in the subject, whether they already have a math degree or not.

    After you’ve taken a grad class on the subject it will become clear that “the little rotating arrows” is just “complex numbers”, and that most of what he is talking about is what in a QFT class will be called “propagators” or “Green’s Functions”.

    What the book really makes clear is that (a) Quantum mechanics is a probabilistic theory, and (b) Complex numbers are intrinsic to QM.

  9. #9 perry
    January 19, 2008

    The Character of Physical Law is another great one.

  10. #10 Jonathan Vos Post
    January 20, 2008

    Chad: I agree with your assessment of QED and second perry’s motion.

    “The thing about Feynman is that you read it, and you say ‘Yes! I understand! I’m doing physics!’ Then you try to solve a problem, and you find that, well, that you’re not Feynman.”

    Ouch. I’d say that this revelation switched me from Physics major at Caltech to Astronomy, and ultimately Math/English. I’m no Feynman. Nobody else was or is, either. Though Hawking, Witten, Wheeler and some others come close…

  11. #11 Derek Lowe
    January 21, 2008

    Chad, I’m glad that you got a chance to take a look at this one, since I recall a few years ago you mentioned that you’d never read it. As an organic chemist (that is, no physicist), it always seemed to me like an excellent attempt to explain a tough area, without oversimplifying too much. It’s good to see that you had the same take.

    That balance – of getting the important ideas across without distorting them in the process – is a talent that very few people have. And to have it to show up so strongly in someone who was so manifestly good at the frontiers of the field is even more rare. It’s no wonder Feynman has the reputation he has. . .

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